With this AUC, RBP4 presented a greater discriminatory ability to diagnose VTDR compared with HbA1c (AUC 0.76; 95% CI: 0.70–0.82; P<0.001), Hs-CRP (AUC 0.71; 95% CI: 0.65–0.78; P<0.001), diabetes duration (AUC 0.77; 95% CI: 0.71–0.83; P<0.001), and HOMA-IR (AUC 0.80; 95% CI: 0.74–0.86; P<0.001). This evidence concerns the gene RBP4 and diabetes mellitus.